Newer designs and manufacturing techniques have driven electronic components to small dimensions and miniaturized many communication devices and systems. Unfortunately, antennas have not been reduced in size at a comparative level and often are one of the larger components used in a smaller communications device. In those communication applications at below 6 GHz frequencies, the antennas become increasingly larger. At very low frequencies, for example, used by submarines or other low frequency communication systems, the antennas become very large, which is unacceptable. It becomes increasingly important in these communication applications to reduce not only antenna size, but also to design and manufacture a reduced size antenna having the greatest gain for the smallest area.
In current, everyday communications devices, many different types of patch antennas, loaded whips, copper springs (coils and pancakes) and dipoles are used in a variety of different ways. These antennas, however, are sometimes large and impractical for a specific application.
Simple flat or patch antennas can be manufactured at low costs and have been developed as antennas for the mobile communication field. The flat antenna or thin antenna is configured, for example, by disposing a patch conductor cut to a predetermined size over a grounded conductive plate through a dielectric material. This structure allows an antenna with high sensitivity over several GHz RF waves to be fabricated in a relatively simple structure. Such an antenna can be easily mounted to appliances, such as a printed circuit board (PCB). However, none of these approaches focused on reducing the size antenna while providing the greatest gain for the smallest area.